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Derivative of log((x-2)/(x+2))

Function f() - derivative -N order at the point
v

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The solution

You have entered [src]
   /x - 2\
log|-----|
   \x + 2/
log(x2x+2)\log{\left(\frac{x - 2}{x + 2} \right)}
log((x - 2)/(x + 2))
Detail solution
  1. Let u=x2x+2u = \frac{x - 2}{x + 2}.

  2. The derivative of log(u)\log{\left(u \right)} is 1u\frac{1}{u}.

  3. Then, apply the chain rule. Multiply by ddxx2x+2\frac{d}{d x} \frac{x - 2}{x + 2}:

    1. Apply the quotient rule, which is:

      ddxf(x)g(x)=f(x)ddxg(x)+g(x)ddxf(x)g2(x)\frac{d}{d x} \frac{f{\left(x \right)}}{g{\left(x \right)}} = \frac{- f{\left(x \right)} \frac{d}{d x} g{\left(x \right)} + g{\left(x \right)} \frac{d}{d x} f{\left(x \right)}}{g^{2}{\left(x \right)}}

      f(x)=x2f{\left(x \right)} = x - 2 and g(x)=x+2g{\left(x \right)} = x + 2.

      To find ddxf(x)\frac{d}{d x} f{\left(x \right)}:

      1. Differentiate x2x - 2 term by term:

        1. The derivative of the constant 2-2 is zero.

        2. Apply the power rule: xx goes to 11

        The result is: 11

      To find ddxg(x)\frac{d}{d x} g{\left(x \right)}:

      1. Differentiate x+2x + 2 term by term:

        1. The derivative of the constant 22 is zero.

        2. Apply the power rule: xx goes to 11

        The result is: 11

      Now plug in to the quotient rule:

      4(x+2)2\frac{4}{\left(x + 2\right)^{2}}

    The result of the chain rule is:

    4(x+2)(x2)(x+2)2\frac{4 \left(x + 2\right)}{\left(x - 2\right) \left(x + 2\right)^{2}}

  4. Now simplify:

    4x24\frac{4}{x^{2} - 4}


The answer is:

4x24\frac{4}{x^{2} - 4}

The graph
02468-8-6-4-2-1010-2525
The first derivative [src]
        /  1      x - 2  \
(x + 2)*|----- - --------|
        |x + 2          2|
        \        (x + 2) /
--------------------------
          x - 2           
(x+2)(x2(x+2)2+1x+2)x2\frac{\left(x + 2\right) \left(- \frac{x - 2}{\left(x + 2\right)^{2}} + \frac{1}{x + 2}\right)}{x - 2}
The second derivative [src]
/     -2 + x\ /  1        1  \
|-1 + ------|*|------ + -----|
\     2 + x / \-2 + x   2 + x/
------------------------------
            -2 + x            
(x2x+21)(1x+2+1x2)x2\frac{\left(\frac{x - 2}{x + 2} - 1\right) \left(\frac{1}{x + 2} + \frac{1}{x - 2}\right)}{x - 2}
The third derivative [src]
  /     -2 + x\ /      1          1              1        \
2*|-1 + ------|*|- --------- - -------- - ----------------|
  \     2 + x / |          2          2   (-2 + x)*(2 + x)|
                \  (-2 + x)    (2 + x)                    /
-----------------------------------------------------------
                           -2 + x                          
2(x2x+21)(1(x+2)21(x2)(x+2)1(x2)2)x2\frac{2 \left(\frac{x - 2}{x + 2} - 1\right) \left(- \frac{1}{\left(x + 2\right)^{2}} - \frac{1}{\left(x - 2\right) \left(x + 2\right)} - \frac{1}{\left(x - 2\right)^{2}}\right)}{x - 2}